Thanks to Marco Bettocchi and Giancarlo Paginelli who responded confirming
my identification of the cones in the Balthasar's paintings at the
Rijksmuseum web site and for pointing out that visible in the larger image
of the painting with the Conus striatus there is another cone that appears
to be a Conus capitaneus (the orange one). Thanks also to Alfonso Pina who
responded informing me that he has a malacological art section right on his
own web site, and which includes many Dutch masters. Look at
http://www.eumed.net/malakos/arte2 . For example, he has there a painting in
private collection in New York by Balthasar van der AST entitled "Ramo de
Flores" (1630) that includes a Conus chaldeus and Conus textile; another
"Flores en jarrón con conchas e insectos",1628-30, entrusted to the National
Gallery, London depicting a Conus striatus and a Conus marmoreus ; another
"Bodegón", (1620) with a Conus pennaceus (?) and a later "Bodegón" (1628),
with Conus striatus and marmoreus (together with a third unidentified cone).
Quite a collection !